Most dental chairs are modular units capable of being equipped with a variety of dental appliances. When so equipped, the appliances are often mounted to a utility box. The utility box is mounted to a swing arm, or attachment arm, that is connected to the chair. The utility box is mounted to the attachment arm so that the appliances are positioned in close proximity to the dental chair for easy access by the dentist. The attachment arm is connected to the base of the chair in a manner such that the arm may be rotated about the chair to allow the dentist to position the appliances on either side of the chair.
The utility box must be level when it is mounted on the attachment arm so that the box and the appliances remain level when the attachment arm is rotated from one side of the chair to the other. Various methods have been developed for levelling the utility box. Prior methods rely upon a vertical post extending from the bottom of the utility box. The post is fit into a collared sleeve on the attachment arm. Numerous set screws, usually eight, are threaded into the collar perpendicular to the longitudinal axis of the post. These set screws are adjusted to bear against the post until the utility box is level.
It is difficult to level utility boxes with such post-type levelling systems. Not only are the set screws difficult to access for adjustment and levelling of the box, but levelling the box is difficult due to the number of set screws.